Control system.



K. A. SIMMON & A. J. HALL.

CONTROL SYSTEM.

APPLICATION mm APR. 6. 1514.

1,241,566. Patentvd Oct. 2, 1917.

INVENTORS q BY 2 ATTORNEY WITNESSES faw/ UNITED erases PATENT omen.

KARL A. SIMMON AND ARTHUR J. HILL, 0F WILKINSBURG, PENNSYLVANIA, ASSIGN-OBS. TO WESTINGHOUSE ELECCDBIG AND MANUEACTUBI'NG COMPANY, A CORPORA-T1017 0]? PENNSYLVAN co yrnor. system. I

Patented Oct. 2, 1917.

Applicationfiledl fifil 6, 191g. een No. stapes.

To all whom it may qoncerm' Be it known that W8,KA.RL A. Smitten, acitizen of the United States, and a resident of Wilkinsbur in the countyof'Alleghn and State of l ennsylvania, and An'rnn'rl HALL, a subject ofthe King of Great Britaim, and a resident of WiIkinSburgQ'inthe' countyof AHeghenyend State of Pennsylvania, have invented a new andusefuhiirprovementin Control Systemsofwhich' he;

following is a specification.

Our invention relates to control systems for dynamo-electric machines,with particular reference toisystems adapted to govern the operation opolyphase induction mo tors through t e agency of regulatable' liquidrheostats.

One of the objects of our invention is to provide a system of classwhich shall embody an aux 4 cult, the completion of. which is effecteddi; rectly by the electrolyte within the rheostat when it reaches apredetermined level.

Another object of our invention is to provide a control system In whicha plurality of auxiliary switches are employed for short-circuiting aliquid rheostat under pre determined conditions, and to provide pie,reliable and effective means, in which no moving parts are employed, foreifecting the closure of the short-circuiting switches at apredetermined level of the electrolyte within the rheostat; v

A still further Object of ourinvention is to provide a so-calledelectrolytic interlock for a liquid rheostat which shall be simple,compact and durable in construction, and which shall perform itsintended functions with positiveness and rapidity, and which, moreover,shall not be subject to wear and mec anical injury.

Heretofore, w en liquid rheostats have been employed, it has beencnstomar to provide short -circuitin switches w ich were interlockedthrong auxiliar switches. that were associated with movab e floats to beraised to cause the interlock switches to complete the energizingcircuits when a redetermined level of electrolyte was attained.

However, much diiliculty has been experienced with interlocking switchesof the fl et type, for the reason th y embody moviary cirable'partswhich are liable to wear and to become displaced through mechanicalshocks and jam. Moreover, a considerable difi'crence of electrolytelevel is essential to effect the closure of such float-actuated switchesand to produce sufficient contact pressure between' the switch membersto result in positive and reliable electrical connections. Furthermore,the surface of the rising elec trolyte -is always disturbed to someextent, which causes a bobbing of the float and, therefore, anintermittent make and break of the circuit and variation in contactpressure.

'According to our present invention, we contemplate providing adequatemeans for overcoming the difficulties heretofore experienced, and tosecure the beneficial and advantageous results hereinbefore menimed-T1Ourinvention may best be understood by reference to the accompanyingdrawing, in which Figure 1 is a diagrammatic view of a system of controlembodying our invention; Figs. 2 and 3 are, respectively, a sectionaiview, and a view, partially in section and partially in side elevationof an electrolytic interlock constructed in accordance with ourinvention, and Fig. 4 is a diagrammatic view of a portion of a systemembodying afnodified formof our invention.

Referring. to the drawing, the system shown comprises a plurality ofsupply circuit conductors 1, 2 and 3; a polyphase induction motor-'4adapted to receive energy therefrom and having primary windings 5 andsecondary windings 6; a liquid rheostat 7 for overning the speed ofoperation of the in notion motor 4, said rheost'at embodying a pluralityof sets of cooperatin electrodes 8 and an electrically operate inletvalve 9 for controlling the admission of electrolyte thereto; adischarge valve 10 and a pneumatically operated device 11 controlled byan electrically operated valve 12 for governing the operation of thedischarge 10; a regulating valve 13 operated by a pneumatic device 14which is controlled by electrically operated valves 15 and 16 forraising and lowering the regulating valve 13 for the purpose of fixinthe height of the electrolyte within the r eostat; a plurality ofelectrically operated line switches 18, 19 and 2Q 1" or establishingconnections between the supply circuit conductors 1, 2 and?) and theprimary windings 5 of the motor 4; a limit switch 22 for automaticallycontrolling the operation of the regulating valve 13; a plurality ofauxiliary electrically operated switches and 25 for short-circuiting thesecondary windings 6 of the motor 4; an

auxiliary interlocking switch 26 that is de- 10 lendent-forits'0perati0n, upon the action of the regulating valve 13; anelectrolytic interlock 27 associated with the liquid rheostat 7 andadapted to coiiperate with the mterlocking switch 26, for energizing theshort-circuiting switches 24 and 25 when the electrolyte has risen to apredetermined level; a naster switch 28 comprising a plurality ofcontact terminals 29 to 34;, inclusive, and a movable contact segment 35adapted to engage the contact terminals along the position-indicatinglines a and b, and abattery B, or other su table source of energy. I

The construction and operation of the rlieostat 7 .andits operatinmechanism, except in so far as the electro ytic interlock 27 isconcerned. is set forth fully in our copending application Serial No.846,287 filed June 20, 1914, and, therefore, only a'brief and generaldescription thereof will be given. In recitin the circuit connections,only the various pieces of apparatus will be enumerated while theseveral conductors will be omitted for the sake of simplicity.

The operating device 14 for the regulating valve 13 comprises a cylinder40 and a movable piston 41. The electrically controlled valve 15 isnormally deenergized and open to admit fluid pressure from a suitablesource (not shown) to the upper side of the piston 11, while the valve16 is normally closed, when deenergized, andestablishes a communicationfrom the lower end of the cylinder 40 to the atmosphere. When theoperating coils of both of the valves 15 and 16 are energized, pressureis exhausted from above the piston 41 and is admitted below it, therebycausing the regulating valve 15 to be raised.

The operating device 11 normally maintains the discharge valve 10 in itsupper position by reason of a spring 42.

Particular reference may now be had to Figs. 2 and 3 in which theauxiliary electrolytic interlock 27 comprises a tubular member 45 which'is screw-threaded at both its ends, one end being provided with a cap46, through the opposite sides of which bushings 47 and contact members48 project. Centrally disposed within the tubular member 45, andprojecting therefrom, are a pinrality of conductin members 49 and 50.The member 49 is o U-shape and the member 50 is disposed intermediatethe sides of the member 49 and is spaced therefrom and held in positionby a plurality of insulating blocks 51.; The U-shaped member 49 isfirmly embedded in a body of insulating ccment 52, or other suitablematerial, and said member is intimately engaged bythe inner end of oneof the members 4:8. The member 19 is further provided with an opening 53throughwhich the other conducting member 48 projects, the latter memberbeing secured to,"and electrically connected with, the conductin.member. 50.

When t e electrolytic interlock 27 is assembled, the member 45 isscrewed .into an opening in therheostat 7, substantially at a heightcorresponding to the maximum level of the electrolyte, as shown in Fig.1, and, hence, the electrolyte servestocom late .a circuit,between thecooperating con ucting memher s s9iand 50 I Assuming that thearrangement of apparatusrand circuit connections are as shown in Fig. 1,the operation of the system is as follows: The master switch 28 is firstmoved into its position a, therebycompleting a circuit from the positiveside of thebattery B through contact terminals 29 and 30, which arebridgedby theconducting segment 35, and energizing .coils of the lineswitches 18, 19 and 20 to the negative side of thebattery. Anothercircuit is established from the con tact terminal 31 of, the masterswitch 28 through the energizin coil of the inlet valve 9'to thebattery, an still another circuit from contact terminal 32 through theener: gizing coils of the discharge valve 12 to the battery iscompleted.

Thus,the switches 18, 19 and 20 are closed to connect the motor 4 to thesup 1y circuit conductors 1, .2, and 3, while the inlet valve 9'isopened to permit the circulation of electrolyte from a suitable source(not shown) into the rheostat 7. Also, the discharge valve 10 is forceddownwardly to its closed position by the operatin device 11. Theadmission of electrolyte glen fills the rheostat 7 to a hei htcorresponding to the upper end of the ischarge valve 13, at which heightthe, electrodes 8 are partially immersed. The motor 4- is, therefore,started into operation.

If the master controller 28 be caused to assume its position b, acircuit is completed from contact terminal 33, which includes theenergizin coil of the valve 15 and cooperatin switc 1 members 22 and 22of the limit switch 22 to'the battery. Another circuit is also completedfrom the contact terminal 34 through the energizing coil of the valve 16to the battery.

Underthese conditions, the operating device 14 raises the regulatingvalve-13 in accordance with the action of the limit switch 22, it beingunderstood that, if the motor current exceeds the value for which thelimit switch 22 is adjusted, the energizing coil of the valve 15 isdecnergized, thereby effectin balanced pressures on the opposite sides 0the iston ll and arresting its movement until the current decreasesbelow a predetermined amount.

Assuming that the operation of the rheo stat 17 has proceeded until theregulating valve 13 occupies its upper position, the in terlockingswitch 26 bridges its 006 crating stationary contact terminals 26 anhence, a circuit is completed from contact terminal 34 of the mastercontroller 28 through interlock switch members 26 and 26", energizingcoils of the short-circuiting switches 24; and 25 and the electrolyticinterlock 27 to the battery, provided, of course, that the electrolytesupply system is operative and that the level of the electrolyte withinthe rheostat 7 is sufiicient to cause the electrolyte itself to bridgethe gap between the contact plates 49 and 50.

It is evident, therefore, that it will be impossible to close theshort-circuiting switches 24 and 25 unless the circulating system isoperating properly and the rhcostat is filled to its maximum height,even though the regulating valve 13 has been moved to its upperposition. The electrolytic interlock 27 is also desirable for the reasonthat its circuit is quickly completed by a relatively small rise ofelectrolyte, and the completion of its circuits by the electrolyteitself is positive and reliable and does not involve the uncertainty ofmovable parts.

Referring to Fig. 4, we have shown a por tion of a modified systemembodying our invention, in which we have made provision for theutilization of alternate current energy in connection with the electroltie interlock, whereby the contact mem ers of the interlock are notsubject to deterioration through the action of electrolysis.

In order to accomplish this end, we employ an alternating current relay60, the energizing coil of which is connected in circuit with thecooperating contact members 49 and 50 of the electrolytic interlock 27,the energy being supplied from one of the phases of the supply circuitor from any other suitable source of alternating current energy.operating stationary and movable contact members 61 and 62 which areadapted to complete the energizing circuit of the coils of theshort-circuiting switches 24 and 25 whenever the electrolytic interlock27 is immersed in electrolyte and the interlock switch members 26 and 26are closed, in the manner hereinbefore set forth.

Although we have found the structure shown in Figs. 2 and 3 to be ofparticular merit, our invention is not limited to its specific details,nor is our invention restricted to any particular type of controlsystems, dynamo-electric machines or liquid rheo- The relay 60 isprovided with 00" such stats, and we desire thereforathat onl icatedlimitations shall be imposed as are in in the appended claims.

We claim as our invention: y

1. The combination with a liquid rheostat and a lurality of auxiliaryspaced and insulateti contact members associated therewith and adaptedto be bridged by the electrolyte, of a source of alternating currentconnected through said contact members,

qwhcrcby electrolysis of said members is prevented.

2. The combination with a liquid rheostat and an electrolytic interlockswitch associated therewith and comprising a plurality of spaced andinsulated contact members adapted to be bridged by the electrol te, ofan auxiliary circuit connected throng said electrolytic interlock switchand a source of alternating current energy for supplying energy to saidcircuit.

3. The combination with a liquid rheostat having an electrolyticinterlock switch associated therewith and adapted to be closed when theelectrolyte reaches a predetermined height, and an alternating currentrelay in circuit with said electrolytic interlock, of means dependentupon said relay for shortcircuiting said rheostat.

4. The combination with a liquid rheostat having an electrolyticinterlock switch associated therewith and adapted to be closed when theelectrolyte reaches a predetermined height, and an alternating currentrelay in circuit with said electrolytic interlock, of an electricallyoperated short-circuiting switch, and a control circuit thereforgoverned by said relay.

5. The combination with a liquid rheostat, a source of alternatingcurrent energy connected thereto, and means for short-circuiting saidrheostat, of a pluralit of insulated contact members associated withsaid rheo-- stat and adapted to be immersed in the electrolyte, underpredetermined conditions, an alternatin current relay connected to saidsource an having a circuit including said contact members, and meanscooperating with said relay for actuating said short-circuitin means.

6. in electrical device comprising a U- shaped conductin member, havingan aperture therein, an e ectrical connection to said U-sha ed member,another conducting member disposed intermediate the arms of saidU-shaped member and an electrical connection projecting through saidaperture to said conducting member.

7. An electrical device comprising a tubular member, a U-shapedelectrically active member having a relatively large aperture in onearm, another electrically active member insulatedly located between thearms of said U-shaped member, means for insulatedly securing saidelectrically active members within said tubular member, and subscribedour names this 31st day of March, spaced electrical conductorsinsulatedly ex- 1914. tending through said sleeve and respectivelyelectrically secured to the unapertured arm of said U shaped member andto said other electrically active member after projecting through salidaperture.

' In testimony whereof, we have hereunto KARL A. SIMMON. ARTHUR J. HALL.

"Witnesses: (1.0. WHITI'AKER,

B. B Hmes,

five cents each, by aiddreesing the "Comminloner of Patent.

Copies of thlspatent may be obtained for Washington, 13.0.

